Mediterranean Diet Lowers Tachyarrhythmia in Paroxysmal AF

A Mediterranean diet with extra virgin olive oil (EVOO) significantly reduced the risk for tachyarrhythmia recurrence after atrial fibrillation (AF) ablation in patients with paroxysmal disease, but the diet had less of an impact on patients with persistent AF, a new study showed.

“An intervention with the Mediterranean diet with EVOO produced a nonsignificant reduction in any atrial tachycardia in a selected population after undergoing atrial fibrillation ablation, but this intervention produced a significant reduction in any atrial tachyarrhythmias in patients with paroxysmal AF,” said Maria Teresa Barrio-Lopez, MD, PhD, an electrophysiologist at University Hospital HM Monteprincipe in Madrid, Spain. She presented results from the PREDIMAR trial here at the Heart Rhythm Society (HRS) 2024 annual meeting.

The PREDIMAR study enrolled 720 patients from the larger PREDIMED study, which showed that patients without AF at enrollment and who followed a Mediterranean diet enriched with EVOO had a 38% lower rate of incidental AF than control individuals.

PREDIMAR evaluated the impact of the diet on arrythmia recurrence in patients after ablation. The patients were randomized in a 1:1 ratio to either the dietary intervention group or the control group.

PREDIMAR Study Results

The overall difference in the rate of AF recurrence in the 3-18 months after ablation between the dietary intervention and control groups was nonsignificant (34.8% vs 37.5%).

However, among the 431 patients with paroxysmal AF, 25.2% in the diet group and 34.7% in the control group had no tachyarrhythmia recurrence, which translates into a 31% lower risk in the diet group.

In this study, the diet was rich in fish, nuts, fruits, and vegetables and was complemented with EVOO. Participants were also permitted moderate wine consumption.

The intervention involved dieticians who remotely followed patients and made periodic telephone calls to encourage them to stay on the diet. Participants had weight and body measurements taken at baseline and at 3, 6, 12, and 18 months and underwent an ECG at 6, 12, and 18 months. Labs were obtained at baseline and at 12 months. Participants were also given educational materials throughout the intervention.

Average scores, based on a scale of 0-13, excluding an item for wine intake, were 7.8 in the diet group and 7.2 in the control group.

Daily average alcohol intake was higher in the diet group than in the control group (9.8 vs 8.2 g), but “the weight of the patient during the study didn’t change in any group,” Barrio-Lopez reported.

Baseline characteristics were similar in the two groups. About 60% were taking antiarrhythmic drugs, and about 84% were taking anticoagulants.

‘A Tour de Force’

PREDIMAR was “really a tour de force,” Christine Albert, MD, MPH, chair of cardiology at the Smidt Heart Institute at the Cedars-Sinai Medical Center in Los Angeles, said during a commentary presented at HRS. “We talk about how we’re going to do these dietary interventions and weight loss and all the risk-factor reduction, and they pulled it off with 700 individuals and also did it in a way that was very novel.”

This is the first large-scale dietary intervention trial of patients with AF. However, Albert noted later in an interview, the Mediterranean diet poses potential challenges for some people with AF.

“The Mediterranean diet recommends that people drink wine, but then there’s clear evidence that abstinence from alcohol actually reduces recurrences of atrial fibrillation, so even though there are a lot of things about the Mediterranean diet that are probably healthy and good for atrial fibrillation, that aspect of it might be working against the patient,” she explained.

The finding that patients in the Mediterranean diet group experienced no significant weight loss could be counterintuitive when it comes to preventing AF. But “you could adapt the diet for AF,” Albert said. You could “leave out the wine and focus more on weight loss if the patient is obese because those are also the pillars of what we’ve learned for patients with atrial fibrillation.”

Making weight loss a key component of the study could be impactful for the American population, she noted. “At least in the United States, that’s a huge part of the risk factors for atrial fibrillation after ablation,” she said.

The remote follow-up component of the PREDIMAR study is also intriguing. “I think what’s most exciting about what they did is, they showed they can do all these things remotely,” Albert added.

Barrio-Lopez had no relevant financial relationships. Albert disclosed relationships with Abbott, Roche Diagnostics, St. Jude Medical, Boston Scientific, Medtronic, and Element Science.